Fuel control system



July 14, 1959 1.. c. DERMOND 2,894,499

FUEL CONTROL SYSTEM Filed Fb. 15, 1957 5 Sheets-Sheet 1 ATTORNEY- July 14, 1959 L. c. DERMOND 2,894,499

,FUEL CONTROL SYSTEM Filed Feb. 13, 1957 3 Sheets-Sheet 2 ATTORNEY.

u y 1959 c. DERMOND 2,894,499

FUEL CONTROL SYSTEM Filed Feb. 13, 1957 3 Sheets Sheet 5 MAN FOLD VA 000M 9 INVENTOR.

ATTORNEY.

United States Patent 2,894,499 FUEL CONTROL SYSTEM Lawrence C. Dermond, Rochester, N.Y., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application February 13, 1957, Serial No. 639,893 12 Claims. (Cl. 123-119) The present invention relates to an improvement in a fuel control system for an internal combustion engine of the fuel injection type. The present invention is of general applicability to fuel injection type engines, however, for the sake of illustration the improvement has been embodied in an injection system of the mass air flow type. A mass air flow type fuel system is one in which the fuel supplied is metered in accordance with the mass of air flowing through the engine. A fuel control system of this general type is shown and described in copending application Serial Number 608,853, filed September 10, 1956, now Patent No. 2,843,098, granted July 15, 1958.

The improvement to which the present case relates involves a mechanism through which the fuel air mixture is enriched during operation of the engine when cold. This invention further relates to a novel device whereby the fuel air ratio is enriched during accelerating conditions before the engine has reached its normal operating temperature.

In the present instance a unique control mechanism has been developed which controls both the cold operation enrichment device and the acceleration enrichment device in such a way that both of these devices are rendered inoperative when the engine reaches a satisfactory operating temperature.

The invention will be hereinafter described in detail.

In the drawings:

Figure 1 is an elevational View of a fuel injection system embodying the subject invention;

Figure 2 is a partially sectioned view of the fuel metering system;

Figure 3 is a fragmentary enrichment of the fuel metering valve;

Figure 4 is an enlarged sectional view of the acceleration and cold enrichment control valves; and

Figure 5 is an enlargement of the acceleration control switch. v I

The fuel control system, per se, is shown and described in copending applications Serial No. 608,797, Olson, filed September 10, 1956, and Serial No. 608,853, Dolza, filed September '10, 1956, Patent No. 2,843,098. Therefore, the system will only be described in such detail as is necessary'to' illustrate the present invention. An air induction passage is shown at and includes a venturi portion 1 2 posteriorly of which is mounted a throttle valve 14 adapted tocontrol the quantity of air flowing through the system. The air induction passage communicates with arnanifold 16 from which a series of ram pipes 18 communicate with the individual cylinders of the engine. Fuel is supplied to the individual ram pipes through nozzles-20'which direct a continuous stream of fuel against the backs of the fuel inlet valves 22. Fuel is supplied to the individual fuel nozzles through passages 24 emanating from a fuel "manifold 26 which is in turn supplied with fuelthfough at passage 28 leading from a metering device indicateddgenerally'at'30. Y 'The' fuel supplying and metering device 30, as shown in Figure 1, is mounted in a housing which includes a case 7 32 and a cover 34.

2,894,499 Patented July 14, 1959 A conduit 36 is formed in cover 34 and is supplied with fuel from a low pressure make-up pump, not shown. A float controlled valve mechanism 38 is also disposed in cover 34 and communicates with conduit 36 through a passage 40 to which filtered fuel is supplied in accordance with the vertical position of the valve member 38 as determined by the position of a pivoted float actuated arm 42. In the normal manner, as float 42 is raised and lowered the valve 38 will shut off or admit fuel into a fuel reservoir 44 provided in casing 32.

i A constant displacement type pump 50 which is driven at engine speed is mounted in the fuel reservoir and is adapted to pump fuel from the reservoir 44 to a conduit 46 leading generally to a metering chamber 48.

Chamber 48 is separated from the fuel reservoir 44 by a partition 51. A bore 52 is formed in the casing of chamber 48 and is adapted to support therein a fuel metering valve 54, the details of which are described in the aforementioned copending application Serial No. 608,853, Dolza. Suflice it to say that conduit 46 supplies fuel to a chamber 56 defined by valve 54 and a removable plug 58. The fuel passes from chamber 56 through a central conduit 60, formed in a slidable plug portion 62 of the valve 54, to a ball check valve 64 seated upon the upper end of the plug 62. Valve 64 blocks the flow of fuel through conduit 60 with a force determined by the rate of a spring 66 which presses upon the valve. The metering valve 54 also includes a cylindrical sleeve 68 having a plurality of circumferentially disposed ports 70 therein which communicate the fuel flowing around ball check'valve 64 to an annularly relieved portion 72 of sleeve 68. The annularly relieved portion 72 communicateswith a passage 74 in the casing wall into which is threaded an adapter plug 76 connecting with the fuel manifold supplying conduit 28.

Sleeve 68 also has a set of peripherally disposed bypass or spill ports 80 above the ports 70. Ports 80 communicate the interior of sleeve 68 to the chamber 48 and thence through a suitable passage back to the fuel reservoir 44. To control the quantity of fuel bypassed through valve 54 back to reservoir 44 and hence the quantity of fuel supplied to the fuel nozzles, a cylinder 82 closed at the upper end is slidably mounted in sleeve 68. The open end of cylinder 82 terminates proximate spill ports 80 in sleeve 68. Fuel pressure within the valve body and which, as noted, is proportional to engine speed tends to move the cylinder 82 upwardly to open ports 80 and thereby bypass fuel to the reservoir.

A linkage mechanism indicated generally at and controlled by a diaphragm 92 exerts a force on top of the valve, as generally described in the aforementioned copending application Serial No. 608,853, Patent No. 2,843,098, which is proportional to the quantity of air flowing through the system. Thus it will be seen that the quantity of fuel supplied to the nozzles 20 by metering valve 54 is proportional to the differential effect of engine speed, as manifested by fuel pressure, and the quantity of air flowing through the system, as manifested by vacuum acting on diaphragm 92.

In order to insure that an enriched fuel air mixture is present when the engine is cold, an enrichment device indicated generally at 96 is provided. Device 96 includes a diaphragm 98 mounted in a casing 100. A rod 102 is centrally fixed to diaphragm 98. Rod 102 is articulated to a lever 104 pivoted at 106 and intermediate the ends of which lever there is articulated an additional rod 108. The other end of rod 108 is articulatedto another pivoted lever 110 the free end 112 of plunger 82 such that as the diaphragm 92 moves upwardly with increased air flow through the induction passage, lever 114 will pivot about fulcrum 112 and thereby depress plunger 82 closing the metering valve spill ports 80 to increase the quantity of fuel supplied to the cylinders.

Enrichment diaphragm 98 is biased to the left by a spring member 120 which causes the pivoted lever 104 to abut an adjustable stop 122 to position the metering valve linkage as shown in Figure 1. Manifold vacuum is adapted to be communicated, by means later to be described, to the right side 124 of the diaphragm chamber under normal operating conditions and overcome the force of spring 120 to shift the pivoted lever 104 against another adjustable stop 126 which in turn shifts the adjustable fulcrum 112 in a counterclockwise direction to reduce the mechanical advantage of the metering valve actuating lever and thereby position the fuel metering link-age system for most economical operation.

An additional lever 128 is pivotally mounted in the metering control device 30 and has one end adapted to engage the top of the metering plunger 82 and the other end articulated to a link 130. Link 130 has fixed to its other end an armature 132 of a solenoid or servo device 134. The solenoid 134 is connected through a lead wire 136 to the ignition system, as described in Serial No. 608,853, in such a way that when the starting motor is energized solenoid 134 is also energized moving armature 132 and rod 130 upwardly and in turn depressing the metering plunger 82 to insure maximum fuel flow to the cylinders during starting of the engine. When the starting motor is deenergized solenoid 134 is also deenergized so that a spring element 138 moves the armature 132 to its lower position moving the lever 128 out of contact with the plunger 82.

The improvement of the present device over those disclosed in the aforenoted copending application resides in the enrichment control device indicated generally at 140 which is adapted to control the cold or maximum power enrichment device 96 as well as providing means whereby the fuel air mixture ratio is enriched during accelerating conditions when the engine is cold. Device 140 includes a casing 142 suitably bored to slidably support a shiftable member 144 having a piston 146 disposed at one end thereof. Piston 146 and casing 142 define a chamber 148 which through conduit 149 is in continuous communication with engine manifold vacuum which tends to move the member 144 downwardly. A lever 150 is mounted on a shaft 152 rotatably supported in casing 142 One end of lever 150 engages an enlarged portion 154 on the sliding member 144 such that the lever 150 and shaft 152 are adapted to be rotated as the sliding member moves within its casing bore. A thermostatic coil 156 is connected to the sliding member 144, either directly or through lever 150, such that when the coil is. cold it retains the member in its upper position permitting the member to be moved downwardly under the influence of manifold vacuum as the coil is heated, inthe manner described in copending application Serial No. 608,853, Patent No. 2,843,098.

An additional bore 160 is formed in casing 142 and includes a shoulder 162 upon which a ball check valve 164 isresiliently retained by a spring 166, the other end of which seats against a plug 168 closing one end of bore 160. Casing 142 has a passage 170 formed therein which is adapted to communicate bore 169 with a manifold vacuum passage 172. An additional passage 174 is formed in, casing 142 and communicates bore 160 with vacuum passage 176 leading to the enrichment device 96. In the position shown, ball check valve 164 prevents manifold vacuum from being delivered to conduit 176. A stud member 180 is slidably mounted in a reduced portion 182 of bore 160. Stud 180 projects from the bore to anextent permitting it to be contacted by end 184 of lever when the latter is rotated in a counterclockwise direction which causes a projection 186 on the stud to engage the ball check valve 164 to move the latter off its seat. Unseating valve 164 permits manifold vacuum to enter passage 176 to shift the cold enrichment device 96 to its normal operating position as described, supra.

Another bore 190 is provided in casing 142 and also includes a ball check valve 192 having a spring 194 tending to bias the valve against a seat 196. A passage 198 is formed in casing 142 and communicates bore 190 with manifold vacuum through a conduit 200. An additional passage 202 communicates the bore 190 with another conduit 204 leading to a vacuum actuated mechanism 206. A stud member 208 is also slidably mounted in a reduced portion 210 of bore 190 and, as shown in the drawing, is adapted to be contacted by end 184 of lever 150 to unseat ball check valve 192 permitting manifold vacuum to communicate with passage 204. As seen in the drawing, ball check valve 192 is unseated when-the engine is cold as manifested by the upper position of sliding member 144.

Mechanism 206 includes a vacuum actuated switch 209 from one terminal of which a lead wire 211 connecting with solenoid =lead 136. Thus, whenever the microswitch 209 is closed solenoid 134 will be energized to shift the metering valve 54 to its maximum fuel flow position as already described in its relation to the enrichment operation when starting the engine. Since mechanism 206 is intended for acceleration purposes, however, it is desired only to provide a metered amount of fuel enrichment to the cylinders for a timed period and then only when the engine is cold. To this end, the vacuum actuated switch mechanism 209 comprises a first diaphragm 212 which is biased against a partition member 214 by a spring 216. A second diaphragm 218 is provided on the opposite side of partition 214 and is similarly biased thereagainst by a spring element 220. Both of the diaphragms 212 and 218 as well as partition 214 are peripherally clamped between casing. members 222 and 224. Switch 209 includes terminals 226 and 228 which are adapted to be connected when contacted by movement of spring member 220.

The chamber 230 defined by casing member 222 and diaphragm 212 is connected with vacuum passage 204. Thus when the engine is cold ball check valve 192 permits manifold vacuum to be transmitted to chamber 230 moving the diaphragm 212 to the left against the force of spring 216. Upon acceleration of the engine manifold vacuum will momentarily drop at which time spring.

216 will move the diaphragm 212 to the right and at the same time causing the air trapped between the diaphragms 212 and 218 to move the latter diaphragm to the right causing spring member 220 to connect terminals 226 and 228 to energize solenoid 134. To insure that solenoid 134 remains energized only for a short interval to provide a metered quantity of fuel, atmospheric bleeds 232 and 234 are formed respectively in casing 224 and diaphragm 218. Thus, after the initial rightward movement of diaphragm 218 atmospheric air will gradually pass through bleeds 232 and 234 equalizing the pressure on both sides of the diaphragm causing the spring 220 to return the diaphragm to its original position abutting partition 214. The leftward movement of spring 220 opens the switch 209 causing the solenoid 134 noted, when the thermostatic coil 156 warms manifoldvacuum in chamber 148 actsonpiston146 to rotate lever 130 in a counterclockwise direction causing end 184 of the lever to move out of engagement with stud 208 and into engagement with stud 180. In this way spring 194 will cause ball check valve 192 to seat within bore 190 cutting off manifold vacuum to the vacuum actuated switch mechanism 209'. At the same time end 184 of lever 150 through stud 180 unseats the ball check valve 164 communicating manifold vacuum to the cold starting enrichment device 96 as already described.

In this way mechanism 140 controls the starting enrichment and acceleration devices 96 and 2% so that both will be operative to enrich the fuel-air mixture when the engine is cold but will render both of these devices inoperative when the engine has reached an operating temperature no longer requiring such fuel enrichment.

I claim:

1. A fuel induction system for an internal combustion engine comprising an air induction passage, a throttle valve for controlling the flow of air through the passage, a pump for supplying fuel under pressure, a metering valve for regulating the quantity of fuel under pressure delivered to the respective cylinders of the engine, means responsive to certain engine operating conditions for controlling said valve during normal operation, additional means for controlling said valve to enrich the fuel-air mixture when the engine is cold, a device for controlling said valve to enrich the fuel air mixture during acceleration of the engine, and a mechanism for rendering said acceleration device inoperative after the engine reaches a given operating temperature.

2. A fuel induction system for an internal combustion engine comprising an air induction passage, a throttle valve for controlling the flow of air through the passage, an engine driven pump for-supplying fuel under pressure, a metering valve for regulating the quantity of fuel under pressure delivered to the respective cylinders of the engine, first means responsive to the mass of air flowing through the induction passage for controlling said valve to increase the quantity of fuel delivered to said engine as the flow of air increases through the induction passage, second means for controlling said Valve to enrich the fuel-air mixture when the engine is cold, a starting enrichment device adapted to be energized during the starting of said engine to increase the quantity of fuel delivered by said valve to the cylinder, a device for controlling said valve to enrich the fuel-air mixture during acceleration of the engine, and a mechanism for rendering said acceleration device and said second valve controlling means inoperative after the engine reaches a given operating temperature.

. 3. A fuel induction system for an internal combustion engine comprising an air induction passage, a throttle valve for controlling the flow of air through the passage, an engine speed responsive pump for supplying fuel under pressure, a metering valve for regulating the quantity of fuel under pressure delivered to the respective cylinders of the engine, means responsive to the mass of air flowing through the induction passage for controlling said valve to increase the quantity of fuel delivered to said engine as the flow of air increases through the induction passage, means for controlling said valve to enrich the fuel-air mixture when the engine is cold, a device for controlling said valve to enrich the fuel-air mixture during acceleration of the engine, and means for interrupting the operation of said acceleration device after a measured quantity of fuel has been supplied for acceleration purposes, said interrupting means comprising a solenoid adapted to operatively engage and move the metering valve to a position permitting maximum fuel flow to the cylinders, a normally open switch mech anism for energizing the solenoid, diaphragm means, means operable by an increase in load on said engine for increasing the pressure on one side of said diaphragm means causing the latter to engage with and close said .switch mechanism, and means for gradually equalizing biasing the diaphragm means in switch-closing direction, and a conduit communicating at one end with said chamher, the other end of said conduitcommunicating with a source of manifold vacuum whereby under normal operating conditions manifold vacuum will move said diaphragm means in a switch-opening direction against the force of said spring.

5. A fuel induction system as defined in claim 3 in which said diaphragm means comprises a washer-like member peripherally mounted within the casing, first and second diaphragm members respectively peripherally mounted between the casing and the opposite faces of the washer-like member, spring elements respectively biasing the diaphragm members into engagement with the washer-like member, a first chamber defined by the first diaphragm and said casing, means communicating manifold vacuum to said first chamber to move the first diaphragm away from said washer-like member, a second chamber defined by said second diaphragm and said casing, said switch mechanism being disposed in said second chamber and adapted to be closed by the movement of said second diaphragm away from the washerlike member, a third chamber defined between the diaphragm members, a bleed opening in said casing communicating said second chamber to atmosphere, and a bleed opening communicating said second and third chambers.

6. A fuel induction system for an internal combustion engine comprising an air induction passage, a throttle valve for controlling the flow of air through the passage, a pump for supplying fuel under pressure, a metering valve for regulating the quantity of fuel under pressure delivered to the respective cylinders of the engine, means responsive to engine demand for controlling said valve, additional means for controlling said valve to enrich the fuel-air mixture when the engine is cold, means for periodi'cally interrupting the operation of said acceleration device after a measured quantity of fuel has been supplied for acceleration purposes, and a mechanism for rendering said acceleration device inoperative after the engine reaches a given operating temperature.

7. A fuel induction system for an internal combustion engine comprising an air induction passage, a throttle valve for controlling the flow of air through the passage, an engine driven pump for supplying fuel under pressure, a metering valve for regulating the quantity of fuel under pressure delivered to the respective cylinders of the engine, means responsive to the mass of air flowing through the induction passage for controlling said valve to increase the quantity of fuel delivered to said engine as the flow of air increases through the induction passage, a servo device adapted to shift the metering valve to a position causing maximum fuel flow to the cylinders, a vacuum actuated mechanism for energizing said servo, means for controlling said valve to enrich the fuel air mixture when the engine is cold, a device for controlling said valve to enrich the fuel air mixture during acceleration of the engine, said acceleration device comprising a valve casing, a first passage communicating said casing with the induction passage posteriorly of said throttle, a movable valve element disposed Within said casing, a second passage leading from said casing and communicating with said vacuum actuated mechanism, said latter valve normally being biased to a position blocking flow between the casing passages, an element adapted to shift said movable valve to a position communicating said first and second passages with each other, and a member responsive to temperature and manifold vacuum to move said element out of operative engagement with said movable valve.

8. Afuel induction system for an internal combustion engine comprising an air induction passage, a throttle valve for controlling theflfiow of air through the passage, an engine driven pump for supplying vfuel under pres sure, a metering valve for regulating the quantity of vfuel under pressure delivered to-the respective cylinders of the engine, means responsive to the mass of air flowing through the induction passage for controlling said valve to increase the quantity of fuel delivered to said engine as the flow of air increases through the induction passage, a servo device adapted to shift said valve to a position causing maximum fuel flow to the cylinders, a vacuumactuated mechanism for energizing said servo, means for controlling said valve to enrich the fuel air mixture when the engine is cold, a device for controlling said valve to enrich the fuel air mixture during acceleration of the engine, said acceleration device comprising a valve casing, a first passage communicating said casing with the induction passage posteriorly of said throttle, a movable valve element disposed within said casing, a second passage leading from said casing and communicating with the vacuum actuated mechanism, said valve normally biased to a position blocking flow between the casing passages, an element adapted to shift said movable valve toa position communicating said first and second passages with each other, a member responsive to temperature and manifold vacuum to move said element out of operative engagement with said movable valve, and said vacuum actuated mechanism including means for deenergizing said servo after a timed interval.

a 9. A fuel induction system for an internal combustion engine comprising an air induction passage, a throttle valve for controlling the flow of air through the passage, means for supplying fuel under pressure, a metering valve for regulating the quantity of fuel under pressure delivered to the respective cylinders of the engine, means responsive to certain engine operating conditions for controlling said valve to increase the quantity of fuel delivered to said engine as power requirements increase, a device for controlling said valve to enrich the fuel-air mixture when theengine is cold, a device for controlling said valve to enrich the fuel-air mixture during acceleration'of the engine, and an enrichment control mechanism having an element operable in accordance with certain engine operating conditions for rendering said cold enrichment device and said acceleration enrichment device inoperative.

10. A fuel induction system as set forth in claim 9 in which said enrichment control mechanism comprises first and second valve devices, first conduit means communicating said valve devices with the induction passage posteriorly of the throttle valve, a second conduit communifirst and third conduits, and lever means adapted to encating the first valve devicew'ith the cold enrichment device, a valve element movably disposed in said first device and biased in-a posit-ion blocking communication between said) first and second conduits when the engine is cold whereby said cold enrichment device is -operative to enrich the fuel-air mixture, a third conduit communicating said second valve device with said acceleration enrichment device, a valve element movably disposed in said second device,vmeans biasing said latter element toward a position blocking communication between said gage and move said latter element to a position communieating said first and third conduits when the engine is cold whereby the acceleration enrichment device is rendered operative to enrich the fuel-air mixture during acceleration.

11. A fuel induction system as set forth in claim 10 in which the lever means is operable by means responsive respectively to temperature and the vacuum in the induction passage posteriorly of the throttle valve, said lever means being moved by said vacuum to disengage the movable valve element of said first device and engage the movable valve element of said second device when engine temperature increases whereby both the cold enrichment and the acceleration enrichment devices are rendered inoperative.

12. A fuel inductionsystem for an internal combustion engine comprising an air induction passage, a throttle valve for controlling the flow of air through the passage, an engine driven pump for supplying fuel under pressure, a metering valve for regulating the quantity of fuel under pressure delivered to the respective cylinders of the engine, means responsive to the mass of air flowing through the induction passage for controlling said valve to increase the quantity of fuel delivered to said engine as the flow of air increases through-the induction passage, means for controlling said valve to enrich the fuel air mixture when the engine is cold, a device for controlling said valve to enrich the fuel vair mixture during acceleration of the engine, an enrichment control mechanism having an element operable in accordance with certain engine operating conditions for rendering said cold enrichment device and said acceleration enrichment device inoperative, means for variably determining the idle position of said throttle valve, said latter means being operatively connected to said element of the enrichment control mechanism.

References Cited in the file of this patent UNITED STATES PATENTS 2,482,956 Wirth et al Sept. 27, 1949 2,641,237 Deschamps June 9, 1953 2,673,556 Reggio Mar. 30, 1954 2,785,669 Armstrong Mar. 19, 1957 v at; 

